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only use AH for EDD version detection, as AL is reserved...

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...according to the spec
This commit is contained in:
Bernd Boeckmann 2023-12-19 21:08:53 +01:00 committed by Kenneth J Davis
parent a5431d9245
commit cab32344bb
1 changed files with 12 additions and 8 deletions
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20
kernel/initdisk.c
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@ -655,15 +655,17 @@ STATIC int LBA_Get_Drive_Parameters(int drive, struct DriveParamS *driveParam, i
init_call_intr(0x13, &regs); init_call_intr(0x13, &regs);
/* LBA not supported at all, or read, write, verify not supported */ if ((regs.flags & 0x01) || regs.b.x != 0xaa55 || (regs.c.x & 0x01) == 0)
if (regs.b.x != 0xaa55 || (regs.flags & 0x01) || (regs.c.x & 1) == 0)
{ {
/* error conditions:
carry set or BX != 0xaa55 => no EDD spec compatible BIOS
CX bit 1 clear => fixed disc access subset not supported */
goto StandardBios; goto StandardBios;
} }
/* version 1.0, 2.0 have different verify */ /* version 1.0, 2.0 have different verify */
if (regs.a.x < 0x2100) if (regs.a.b.h < 0x21)
LBA_WRITE_VERIFY = 0x4301; /* problematic if INT13 is hooked by LBA_WRITE_VERIFY = 0x4301; /* may be problematic if INT13 is hooked by
different controllers / drivers */ different controllers / drivers */
/* query disk size and DMA handling, geometry is queried later by INT13,08 */ /* query disk size and DMA handling, geometry is queried later by INT13,08 */
@ -676,9 +678,9 @@ STATIC int LBA_Get_Drive_Parameters(int drive, struct DriveParamS *driveParam, i
regs.d.b.l = drive; regs.d.b.l = drive;
init_call_intr(0x13, &regs); init_call_intr(0x13, &regs);
/* error or DMA boundary errors not handled transparently */
if (regs.flags & 0x01) if (regs.flags & 0x01)
{ {
/* carry flag set indicates failed LBA disk parameter query */
goto StandardBios; goto StandardBios;
} }
@ -719,11 +721,13 @@ STATIC int LBA_Get_Drive_Parameters(int drive, struct DriveParamS *driveParam, i
if (lba_bios_parameters.information & 1) if (lba_bios_parameters.information & 1)
{ {
driveParam->descflags |= DF_DMA_TRANSPARENT; /* DMA boundary errors are handled transparently */ /* DMA boundary errors are handled transparently */
driveParam->descflags |= DF_DMA_TRANSPARENT;
} }
StandardBios: /* old way to get parameters */ StandardBios: /* get disk geometry, and if LBA is not enabled, also size */
if (firstPass && (InitKernelConfig.Verbose >= 1)) printf("Retrieving CHS values for drive\n"); if (firstPass && (InitKernelConfig.Verbose >= 1))
printf("Retrieving CHS values for drive\n");
regs.a.b.h = 0x08; regs.a.b.h = 0x08;
regs.d.b.l = drive; regs.d.b.l = drive;